Question

Помогите, пожалуйста, с самостоятельной по алгебре!

Answer 1

Ответ:

Задание 1.

$1) \: (3x - 5)(2x + 7) = 6 {x}^{2} + 21x - 10x - 35 = 6 {x}^{2} + 11x - 35 \\ 2) \: ( - 2 - y) ({y}^{2} + 3) = - 2 {y}^{2} - 6 - {y}^{3} - 3y = - {y}^{3} - 2 {y}^{2} - 3y - 6 \\ 3) \: (3 {a}^{2} - b)(4 {a}^{2} + 3b) = 12 {a}^{4} + 9 {a}^{2} b - 4 {a}^{2} b - 3 {b}^{2} = 12 {a}^{4} + 5 {a}^{2} b - 3 {b}^{2}$

Задание 2.

$1) \: (x + 3)(x - 7) - 4x(5 - 2x) = {x}^{2} - 7x + 3x - 21 - 20x + 8 {x}^{2} = 9 {x}^{2} - 24x - 21 \\ 2) \: (y + 2)(y - 6) + (y + 3)(y - 4) = ({y}^{2} - 6y + 2y - 12) + ( {y}^{2} - 4y + 3y - 12) = {y}^{2} - 4y - 12 + {y}^{2} - y - 12 = 2 {y}^{2} - 5y - 24$

Задание 3.

$(3x + 5)(2x + 1) = (6x + 5)(x - 3) + 7 \\ 6 {x}^{2} + 3x + 10x + 5 = 6 {x}^{2} - 18x + 5x - 15 + 7 \\ 6 {x}^{2} + 13x + 5 = 6 {x}^{2} - 13x - 8 \\ 26x = - 13 \\ x = - \frac{1}{2}$